Epwforge

MCP server for EPWForge — give Claude, Cursor, and other AI agents the ability to generate, morph, and download weather files for building energy simulation.

Status: 0.10.0 (Python). Four consolidated tools — find_station, analyze_weather, chart_weather, generate_weather_file. Production backend, all tier features wired in. Mirrored 1:1 by the hosted MCP at https://epwforge.com/api/mcp (Claude Web / hosted MCP clients get the same surface).

What is EPWForge?

EPWForge generates and morphs weather files (.epw, .ddy, .csv) for building energy simulation tools — EnergyPlus, OpenStudio, IES VE, eQUEST, and any workflow that consumes EPW. The platform supports:

• TMYx generation anywhere — typical meteorological years synthesized from ERA5 reanalysis (1950–present) for any global lat/lon, or passthrough of published OneBuilding TMYx files for ~17,000 known stations.
• AMY (Actual Meteorological Year) — historical hourly weather for any specific year since 1950. Useful for stress-testing against observed extremes.
• CMIP6 climate morphing — apply SSP1-2.6 / SSP2-4.5 / SSP3-7.0 at horizons 2030–2100 across 7 warming percentiles, plus SSP5-8.5 as an opt-in extreme stress test. SSP3-7.0 is the recommended high-end for design. Belcher 2005 mean-shift hybridised with UKCP18 / NOAA Atlas 14 diurnal anomalies.
• Urban Heat Island adjustment — Stewart & Oke 2012 Local Climate Zone presets (suburban / urban / dense_urban).
• Extreme event injection — heatwave, cold snap, hot-humid, cold-windy, wildfire smoke. Per-event intensity 1–10, AR6-auto-fill under an SSP. Events stitched at the baseline's hottest / coldest 14-day window.
• ASHRAE 169 design conditions — full percentile bins (0.4 / 1 / 2 cooling, 99.6 / 99 heating, WB / DP / Enth variants), computed from the modified hourly distribution.
• Output formats — EnergyPlus (.epw + .ddy + .stat), CSV hourly, PVsyst, ESP-r .clm. Bundled .zip available.

Tools

Four consolidated tools. Operations that were once separate tools (batch, ensemble, design-day, etc.) are now parameters on these four — see the deprecation map below.

Tool	What it does	Auth
find_station	Search the ~17,000-station GuzzStations catalog by name, country, or coordinates. Optional compact=True returns just the newest TMYx per station (6–10× smaller responses for chained agent workflows).	none
analyze_weather	Statistical summary of an EPW. Three modes: url= (single file), urls=[] (2–10 file comparison), config={...} (synthesize a morphed scenario from lat/lon — no EPW content returned). Optional include_full_ashrae, include_improbability, include_idf.	none
chart_weather	Inline SVG chart. Single-EPW types: diurnal, temp_carpet, wind_rose, monthly_boxplot, utci_carpet, economizer_carpet, pv_tilt_azimuth, solar_under_events. Multi-EPW type: comparison.	none
generate_weather_file	Generate and return a downloadable weather file with the full morph stack. Format = epw / ddy / csv / zip / pvsyst. Supports ensemble=true (all SSPs at once).	API key + credits

Deprecation map (v0.2.0 consolidation)

Migrating from a pre-0.2.0 agent script? Old → new:

Old tool	Now reached via
generate_design_day	generate_weather_file(format="ddy")
generate_ensemble	generate_weather_file(ensemble=true)
generate_batch	Loop generate_weather_file client-side, or generate_weather_file(scenarios=[...])
get_station_epw	Pass the epw_url from find_station to analyze_weather / chart_weather, or download directly
analyze_epw	analyze_weather(url=...)
compare_scenarios	analyze_weather(config={...}) per scenario, or analyze_weather(urls=[...]) for static EPWs
chart_diurnal_profile	chart_weather(url=..., chart_type="diurnal")
chart_compare_scenarios	chart_weather(urls=[...], chart_type="comparison")
explore_design_conditions	Removed in v0.9.0. Functionality being folded into analyze_weather with a scenario-grid widget (Phase 3 redesign — see brain-central notes).

Full reference

The canonical reference lives on the EPWForge site:

• epwforge.com/docs — every parameter, example call, error codes, methodology references, validation numbers.
• Tool docstrings in python/src/epwforge_mcp/server.py — read-it-in-IDE source of truth, lifted into the docs page above.
• tools/list on the running server — most accurate, reflects the exact version installed.

Quick examples

# Find the nearest station to a coordinate, with token-efficient response
find_station(lat=40.71, lon=-74.01, compact=True)

# Analyze a published TMYx file
analyze_weather(url="https://.../USA_NY_New.York-JFK.AP.744860_TMYx.2011-2025.epw")

# Compare cooling design conditions across 3 cities
analyze_weather(urls=["...A.epw", "...B.epw", "...C.epw"])

# Synthesize a stress-test scenario at any lat/lon (no auth needed — no EPW content returned)
analyze_weather(
    config={
        "lat": 40.71, "lon": -74.01,
        "ssp": "ssp370", "year": 2050, "percentile": 75,
        "uhi": "urban",
        "events": "heatwave",
        "intensity": "heatwave:6",
        "event_duration": 14,
    },
    include_full_ashrae=True,
    include_improbability=True,
)

# Inline SVG chart (zero context cost vs base64 PNG)
chart_weather(url="https://.../...epw", chart_type="temp_carpet")

# Generate the actual downloadable file (auth + credits)
generate_weather_file(
    lat=40.71, lon=-74.01,
    format="zip",       # EPW + DDY + STAT bundled
    ssp="ssp370", year=2090, percentile=90,
    uhi="urban",
    events="heatwave,hothumid", event_duration=14,
    smoke_enabled=True, smoke_intensity=5,
)

Install

pip install epwforge-mcp
# or, with uv:
uvx epwforge-mcp

Requires Python ≥ 3.10.

Connecting to Claude / Cursor / other MCP clients

Add to your MCP client config (Claude Desktop's claude_desktop_config.json, Cursor's MCP settings, VS Code's MCP extension, Goose):

{
  "mcpServers": {
    "epwforge": {
      "command": "epwforge-mcp",
      "env": {
        "EPWFORGE_API_KEY": "sk_live_..."
      }
    }
  }
}

Get an API key (free or paid) at epwforge.com/account. Read-only tools (find_station, analyze_weather, chart_weather) work without a key; only generate_weather_file requires one.

For browser-based MCP clients (Claude Web, ChatGPT, etc.), use the hosted endpoint:

https://epwforge.com/api/mcp

Credits & pricing

Credit-based. Every plan gets every feature; credits gate volume.

Plan	Price	Credits/mo	$/credit
Free	$0	5 lifetime	n/a
Starter	$49	10	$4.90
Pro	$149	50	$2.98
Pro+	$249	100	$2.49

One-time top-up packs available: 5 cr / $50, 20 cr / $180, 50 cr / $400.

Tool call	Cost
find_station, analyze_weather, chart_weather	0 credits (no auth needed)
generate_weather_file — single file (epw / ddy / csv / pvsyst)	1 credit
generate_weather_file — bundle (zip with 4+ files, AMY, all-SSP)	2 credits
generate_weather_file — CMIP6 ensemble (per-model)	10 credits

Out-of-credits returns HTTP 402 with hints pointing at top-up packs and subscription upgrades. The MCP surfaces 402s as ToolError with a hint field; in agent loops this naturally routes the user to the upgrade flow.

Environment variables

Variable	Purpose	Default
EPWFORGE_API_KEY	Bearer token for generate_weather_file	none — read-only tools work without
EPWFORGE_BASE_URL	Override the API host (mainly for testing against a local backend)	https://epwforge.com

Behavior notes

• Anon-safe by construction. find_station, analyze_weather, and chart_weather never return EPW content; config-mode analyze_weather synthesizes the morphed scenario server-side and returns only stats. Only generate_weather_file touches credits / auth.
• agent_guidance field. Most responses include a short, judgment-shaping string the model can use to choose the right next step (e.g. "nearest station is 8 km — use it directly" vs "nearest station is 250 km — consider config-mode synthesis").
• Inline SVG charts rather than base64 PNG — typically 10× smaller in context. Each chart's svg_size_kb is reported up-front so agents can self-budget. Charts >50 KB auto-upload to Vercel Blob and return svg_url instead.
• Compound events. events="heatwave,hothumid" blends hothumid's humidity onto the heatwave at 50%. events="coldsnap,coldwindy" blends wind onto the cold snap. Secondary folds into the primary stitch — not stitched separately.
• Event placement. Events anchor at the cell's hottest day (heat family) or coldest day (cold family), then center for the requested duration. The peak day's diurnal cycle is sustained across the event — a 30-day request gets 30 days of peak heat, not a stretched 14-day shape.
• AR6 SSP auto-fill. With an SSP active, unspecified event intensities auto-fill from IPCC AR6 ensemble factors for the cell's region. Cold-family events stay at intensity 5 (no future amplification) because recent observations don't yet support the AR6 ensemble's cold-side dampening. Pass intensity_auto=false to disable.

Development

git clone https://github.com/guzz-labs/epwforge-mcp
cd epwforge-mcp/python
uv sync
uv run epwforge-mcp   # runs the stdio server

Run tests:

.venv/bin/python -m pytest tests/ -v   # 30+ tests

Test against a local API:

EPWFORGE_BASE_URL=http://localhost:3000 \
EPWFORGE_API_KEY=sk_live_... \
uv run epwforge-mcp

Version sync (before publishing):

python3 scripts/check-versions.py            # verify all 5 version strings agree
python3 scripts/check-versions.py --set 0.9.3 # bump everywhere atomically

Links

• Website: epwforge.com
• Documentation: epwforge.com/docs
• REST API reference: epwforge.com/api-docs
• MCP connection guide: epwforge.com/mcp
• Methodology + validation: epwforge.com/transparency
• Pricing: epwforge.com/pricing
• Hosted MCP endpoint: https://epwforge.com/api/mcp
• PyPI: pypi.org/project/epwforge-mcp
• Parent platform: Guzzlabs
• Issues: github.com/guzz-labs/epwforge-mcp/issues

License

MIT